# flake8: noqa
# yapf: disable

# Copyright 2023 The Google Research Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Library of instructions."""
import collections
import json
import random
import re
import string
from typing import Dict, Optional, Sequence, Union

try:
    import langdetect
except ImportError:
    langdetect = None

from absl import logging

import opencompass.datasets.IFEval.instructions_util as instructions_util

_InstructionArgsDtype = Optional[Dict[str, Union[int, str, Sequence[str]]]]

_LANGUAGES = instructions_util.LANGUAGE_CODES

# The relational operation for comparison.
_COMPARISON_RELATION = ('less than', 'at least')

# The maximum number of sentences.
_MAX_NUM_SENTENCES = 20

# The number of placeholders.
_NUM_PLACEHOLDERS = 4

# The number of bullet lists.
_NUM_BULLETS = 5

# The options of constrained response.
_CONSTRAINED_RESPONSE_OPTIONS = ('My answer is yes.', 'My answer is no.',
                                 'My answer is maybe.')

# The options of starter keywords.
_STARTER_OPTIONS = ('I would say', 'My answer is', 'I believe',
                    'In my opinion', 'I think', 'I reckon', 'I feel',
                    'From my perspective', 'As I see it', 'According to me',
                    "As far as I'm concerned", 'To my understanding',
                    'In my view', 'My take on it is', 'As per my perception')

# The options of ending keywords.
# TODO(jeffreyzhou) add more ending options
_ENDING_OPTIONS = ('Any other questions?',
                   'Is there anything else I can help with?')

# The number of highlighted sections.
_NUM_HIGHLIGHTED_SECTIONS = 4

# The section spliter.
_SECTION_SPLITER = ('Section', 'SECTION')

# The number of sections.
_NUM_SECTIONS = 5

# The number of paragraphs.
_NUM_PARAGRAPHS = 5

# The postscript marker.
_POSTSCRIPT_MARKER = ('P.S.', 'P.P.S')

# The number of keywords.
_NUM_KEYWORDS = 2

# The occurrences of a single keyword.
_KEYWORD_FREQUENCY = 3

# The occurrences of a single letter.
_LETTER_FREQUENCY = 10

# The occurrences of words with all capital letters.
_ALL_CAPITAL_WORD_FREQUENCY = 20

# The number of words in the response.
_NUM_WORDS_LOWER_LIMIT = 100
_NUM_WORDS_UPPER_LIMIT = 500


class Instruction:
    """An instruction template."""

    def __init__(self, instruction_id):
        self.id = instruction_id

    def build_description(self, **kwargs):
        raise NotImplementedError('`build_description` not implemented.')

    def get_instruction_args(self):
        raise NotImplementedError('`get_instruction_args` not implemented.')

    def get_instruction_args_keys(self):
        raise NotImplementedError(
            '`get_instruction_args_keys` not implemented.')

    def check_following(self, value):
        raise NotImplementedError('`check_following` not implemented.')


class ResponseLanguageChecker(Instruction):
    """Check the language of the entire response."""

    def build_description(self, *, language=None):
        """Build the instruction description.

        Args:
          language: A string representing the expected language of the response. The
            language has to comply to the 97 types defined in
            `langid.py` (https://pypi.org/project/langid/1.1.5/), which follows
            ISO 639-1 codes (https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes);
            for example, `en` for English, `zh` for Chinese, `fr` for French.

        Returns:
          A string representing the instruction description.
        """
        self._language = language
        if self._language is None:
            self._language = random.choice(list(_LANGUAGES.keys()))
        # TODO(tianjianlu): opens the description generation to more choices.
        self._description_pattern = (
            'Your ENTIRE response should be in {language} language, no other '
            + 'language is allowed.')
        return self._description_pattern.format(
            language=_LANGUAGES[self._language])

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'language': self._language}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['language']

    def check_following(self, value):
        """Check if the language of the entire response follows the
        instruction.

        Args:
          value: A string representing the response.

        Returns:
          True if the language of `value` follows instruction; otherwise False.
        """
        assert isinstance(value, str)

        try:
            return langdetect.detect(value) == self._language
        except langdetect.LangDetectException as e:
            # Count as instruction is followed.
            logging.error('Unable to detect language for text %s due to %s',
                          value, e)  # refex: disable=pytotw.037
            return True


class NumberOfSentences(Instruction):
    """Check the number of sentences."""

    def build_description(self, *, num_sentences=None, relation=None):
        """Build the instruction description.

        Args:
          num_sentences: An integer specifying the number of sentences as a
            threshold.
          relation: A string in (`less than`, `at least`), defining the relational
            operator for comparison.
            Two relational comparisons are supported for now:
            if 'less than', the actual number of sentences < the threshold;
            if 'at least', the actual number of sentences >= the threshold.

        Returns:
          A string representing the instruction description.
        """
        # The number of sentences as a threshold for comparison.
        self._num_sentences_threshold = num_sentences
        if (self._num_sentences_threshold is None
                or self._num_sentences_threshold < 0):
            self._num_sentences_threshold = random.randint(
                1, _MAX_NUM_SENTENCES)

        if relation is None:
            self._comparison_relation = random.choice(_COMPARISON_RELATION)
        elif relation not in _COMPARISON_RELATION:
            raise ValueError(
                'The supported relation for comparison must be in '
                f'{_COMPARISON_RELATION}, but {relation} is given.')
        else:
            self._comparison_relation = relation

        self._description_pattern = (
            'Your response should contain {relation} {num_sentences} sentences.'
        )
        return self._description_pattern.format(
            relation=self._comparison_relation,
            num_sentences=self._num_sentences_threshold)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'num_sentences': self._num_sentences_threshold,
            'relation': self._comparison_relation
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_sentences', 'relation']

    def check_following(self, value):
        """Check if the number of sentences follows the instruction.

        Args:
          value: A string representing the response.

        Returns:
          True if the response follows the instruction.

        Raise:
            ValueError if the string in `instruction_args` is not in
            [`less_than`, `at_least`].
        """
        num_sentences = instructions_util.count_sentences(value)
        if self._comparison_relation == _COMPARISON_RELATION[0]:
            return num_sentences < self._num_sentences_threshold
        elif self._comparison_relation == _COMPARISON_RELATION[1]:
            return num_sentences >= self._num_sentences_threshold


class PlaceholderChecker(Instruction):
    """Check the placeholders in template writing."""

    def build_description(self, *, num_placeholders=None):
        """Build the instruction description.

        Args:
          num_placeholders: An integer denoting the minimum number of
            placeholders required in the response.

        Returns:
          A string representing the instruction description.
        """
        self._num_placeholders = num_placeholders
        if self._num_placeholders is None or self._num_placeholders < 0:
            self._num_placeholders = random.randint(1, _NUM_PLACEHOLDERS)
        self._description_pattern = (
            'The response must contain at least {num_placeholders} placeholders '
            + 'represented by square brackets, such as [address].')
        return self._description_pattern.format(
            num_placeholders=self._num_placeholders)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'num_placeholders': self._num_placeholders}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_placeholders']

    def check_following(self, value):
        """Check if the number of placeholders follows the instruction.

        Args:
          value: A string representing the response.

        Returns:
          True if the actual number of placeholders in the response is greater than
          or equal to `num_placeholders`; otherwise, False.
        """
        placeholders = re.findall(r'\[.*?\]', value)
        num_placeholders = len(placeholders)
        return num_placeholders >= self._num_placeholders


class BulletListChecker(Instruction):
    """Checks the bullet list in the prompt."""

    def build_description(self, *, num_bullets=None):
        """Build the instruction description.

        Args:
          num_bullets: An integer specifying the exact number of bullet lists
            that is required to appear in the response.

        Returns:
          A string representing the instruction description.
        """
        self._num_bullets = num_bullets
        if self._num_bullets is None or self._num_bullets < 0:
            self._num_bullets = random.randint(1, _NUM_BULLETS)
        self._description_pattern = (
            'Your answer must contain exactly {num_bullets} bullet points. ' +
            'Use the markdown bullet points such as:\n' +
            '* This is point 1. \n' + '* This is point 2')
        return self._description_pattern.format(num_bullets=self._num_bullets)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'num_bullets': self._num_bullets}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_bullets']

    def check_following(self, value):
        r"""Check if the number of bullet lists meets the requirement.

        Args:
          value: A string representing the response. The response is expected to
            contain some bullet lists that start with `\*`.

        Returns:
          True if the actual number of bullet lists in the response meets the
          requirement.
        """
        bullet_lists = re.findall(r'^\s*\*[^\*].*$', value, flags=re.MULTILINE)
        bullet_lists_2 = re.findall(r'^\s*-.*$', value, flags=re.MULTILINE)
        num_bullet_lists = len(bullet_lists) + len(bullet_lists_2)
        return num_bullet_lists == self._num_bullets


class ConstrainedResponseChecker(Instruction):
    """Checks the constrained response."""

    def build_description(self):
        """Build the instruction description."""
        # A sequence of string(s) representing the options of the expected response.
        self._constrained_responses = _CONSTRAINED_RESPONSE_OPTIONS
        self._description_pattern = (
            'Answer with one of the following options: {response_options}')
        return self._description_pattern.format(
            response_options=self._constrained_responses)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks if the response matches the constrained options.

        Args:
          value: A string representing the response.

        Returns:
          True if the actual response contains one of the options in the constrained
          responses; otherwise False.
        """
        value = value.strip()
        for constrained_response in self._constrained_responses:
            if constrained_response in value:
                return True
        return False


class ConstrainedStartChecker(Instruction):
    """Checks the response start."""

    def build_description(self, *, starter=None):
        """Build the instruction description.

        Args:
          starter: A string representing the keyword that the response should start
            with.

        Returns:
          A string representing the instruction description.
        """
        self._starter = starter.strip() if isinstance(starter,
                                                      str) else starter
        if self._starter is None:
            self._starter = random.choice(_STARTER_OPTIONS)
        self._description_pattern = (
            'During the conversation, when it is your turn, ' +
            'please always start with {starter}')
        return self._description_pattern.format(starter=self._starter)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'starter': self._starter}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['starter']

    def check_following(self, value):
        """Checks if the response starts with the constrained keyword or
        phrase.

        Args:
          value: A string representing the response.

        Returns:
          True if the response starts with the given phrase or keyword that is
          contained in `instruction_args`; otherwise, False.
        """
        response_pattern = r'^\s*' + self._starter + r'.*$'
        response_with_constrained_start = re.search(response_pattern,
                                                    value,
                                                    flags=re.MULTILINE)
        return True if response_with_constrained_start else False


class HighlightSectionChecker(Instruction):
    """Checks the highlighted section."""

    def build_description(self, *, num_highlights=None):
        """Build the instruction description.

        Args:
          num_highlights: An integer specifying the minimum number of highlighted
            sections.

        Returns:
          A string representing the instruction description.
        """
        self._num_highlights = num_highlights
        if self._num_highlights is None or self._num_highlights < 0:
            self._num_highlights = random.randint(1, _NUM_HIGHLIGHTED_SECTIONS)

        self._description_pattern = (
            'Highlight at least {num_highlights} sections in your answer with '
            + 'markdown, i.e. *highlighted section*.')

        return self._description_pattern.format(
            num_highlights=self._num_highlights)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'num_highlights': self._num_highlights}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_highlights']

    def check_following(self, value):
        """Checks if the number of highlighted sections meets the requirement.

        Args:
          value: a string representing the response. The response is expected to
            contain highlighted sections in the format of *highlighted*.

        Returns:
          True if the actual number of highlighted sections in the format of
          *highlighted sections* meets the minimum requirement; otherwise False.
        """
        num_highlights = 0
        highlights = re.findall(r'\*[^\n\*]*\*', value)
        double_highlights = re.findall(r'\*\*[^\n\*]*\*\*', value)
        for highlight in highlights:
            if highlight.strip('*').strip():
                num_highlights += 1
        for highlight in double_highlights:
            if highlight.removeprefix('**').removesuffix('**').strip():
                num_highlights += 1

        return num_highlights >= self._num_highlights


class SectionChecker(Instruction):
    """Checks the sections."""

    def build_description(self, *, section_spliter=None, num_sections=None):
        """Build the instruction description.

        Args:
          section_spliter: A string represents the section spliter keyword that
            marks a new section, i.e., `Section` or `SECTION`.
          num_sections: An integer specifying the number of sections.

        Returns:
          A string representing the instruction description.
        """
        self._section_spliter = section_spliter.strip() if isinstance(
            section_spliter, str) else section_spliter
        if self._section_spliter is None:
            self._section_spliter = random.choice(_SECTION_SPLITER)

        self._num_sections = num_sections
        if self._num_sections is None or self._num_sections < 0:
            self._num_sections = random.randint(1, _NUM_SECTIONS)

        self._description_pattern = (
            'Your response must have {num_sections} sections. Mark the beginning '
            + 'of each section with {section_spliter} X, such as:\n' +
            '{section_spliter} 1\n' + '[content of section 1]\n' +
            '{section_spliter} 2\n' + '[content of section 2]')

        return self._description_pattern.format(
            num_sections=self._num_sections,
            section_spliter=self._section_spliter)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'section_spliter': self._section_spliter,
            'num_sections': self._num_sections
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['section_spliter', 'num_sections']

    def check_following(self, value):
        """Checks the response contains multiple sections.

        Args:
          value: A string representing the response. The response is expected
            to contain multiple sections (number of sections is greater than 1).
            A new section starts with `Section 1`, where the number denotes the
            section index.

        Returns:
          True if the number of sections in the response is greater than or equal to
          the minimum number of sections; otherwise, False.
        """
        section_splitter_patten = r'\s?' + self._section_spliter + r'\s?\d+\s?'
        sections = re.split(section_splitter_patten, value)
        num_sections = len(sections) - 1
        return num_sections >= self._num_sections


class ParagraphChecker(Instruction):
    """Checks the paragraphs."""

    def build_description(self, *, num_paragraphs=None):
        """Build the instruction description.

        Args:
          num_paragraphs: An integer specifying the number of paragraphs.

        Returns:
          A string representing the instruction description.
        """
        self._num_paragraphs = num_paragraphs
        if self._num_paragraphs is None or self._num_paragraphs < 0:
            self._num_paragraphs = random.randint(1, _NUM_PARAGRAPHS)

        self._description_pattern = (
            'There should be {num_paragraphs} paragraphs. ' +
            'Paragraphs are separated with the markdown divider: ***')

        return self._description_pattern.format(
            num_paragraphs=self._num_paragraphs)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'num_paragraphs': self._num_paragraphs}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_paragraphs']

    def check_following(self, value):
        """Checks the response contains required number of paragraphs.

        Args:
          value: A string representing the response. The response may contain
            paragraphs that are separated by the markdown divider: `***`.

        Returns:
          True if the actual number of paragraphs is the same as required;
          otherwise, False.
        """
        paragraphs = re.split(r'\s?\*\*\*\s?', value)
        num_paragraphs = len(paragraphs)

        for index, paragraph in enumerate(paragraphs):
            if not paragraph.strip():
                if index == 0 or index == len(paragraphs) - 1:
                    num_paragraphs -= 1
                else:
                    return False

        return num_paragraphs == self._num_paragraphs


class PostscriptChecker(Instruction):
    """Checks the postscript."""

    def build_description(self, *, postscript_marker=None):
        """Build the instruction description.

        Args:
          postscript_marker: A string containing the keyword that marks the start
            of the postscript section.

        Returns:
          A string representing the instruction description.
        """
        self._postscript_marker = postscript_marker.strip() if isinstance(
            postscript_marker, str) else postscript_marker
        if self._postscript_marker is None:
            self._postscript_marker = random.choice(_POSTSCRIPT_MARKER)

        self._description_pattern = (
            'At the end of your response, please explicitly add a postscript '
            + 'starting with {postscript}')

        return self._description_pattern.format(
            postscript=self._postscript_marker)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'postscript_marker': self._postscript_marker}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['postscript_marker']

    def check_following(self, value):
        """Checks if the response follows the postscript format.

        Args:
          value: a string representing the response. The response is expected to
            contain a postscript section.

        Returns:
          True if the response contains a postscript section starting with
          the keyword containing in the `instruction_args`; otherwise False.
        """
        value = value.lower()
        if self._postscript_marker == 'P.P.S':
            postscript_pattern = r'\s*p\.\s?p\.\s?s.*$'
        elif self._postscript_marker == 'P.S.':
            postscript_pattern = r'\s*p\.\s?s\..*$'
        else:
            postscript_pattern = r'\s*' + self._postscript_marker.lower(
            ) + r'.*$'
        postscript = re.findall(postscript_pattern, value, flags=re.MULTILINE)
        return True if postscript else False


class RephraseChecker(Instruction):
    """Checks the repharse."""

    def build_description(self, *, original_message):
        """Build the instruction description.

        Args:
          original_message: A string representing the original message. The
            rephrased response should only change its words/sentences in between
            its two asterisks, for example, *change me*. Both original and rephrased
            messages should contain the changes in the form of *change me*.

        Returns:
          A string representing the instruction description.
        """
        if not self.is_change(original_message):
            raise ValueError(
                f'Message {original_message} does not contain changes '
                'in the form of *change me*.')

        self._reference_without_change = original_message
        self._description = (
            'Rephrasing: Your rephrased response should only' +
            'change the words/sentences in between two asterisks' +
            'such as *change me*.')
        return self._description

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'original_message': self._reference_without_change}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['original_message']

    def check_following(self, value):
        r"""Checks if the rephrasing follows the instruction.

        Args:
          value: A string representing the response, which is expected to rephras
            the string of `instruction_args`.

        Returns:
          True if `value` and `instruction_args` only differ by the words/sentences
          in between two asterisks such as *change me*; otherwise, False.
        """

        if not self.is_change(value):
            raise ValueError(f'value {value} does not contain '
                             'changes in the form of *change me*.')

        response_without_changes = self.strip_changes(value)
        reference_without_changes = self.strip_changes(
            self._reference_without_change)

        return response_without_changes == reference_without_changes

    def is_change(self, response):
        """Check if there is change in the response in the form of *change
        me*."""
        return re.search(r'\*.*\*', response)

    def strip_changes(self, response):
        """Strips off the changes."""
        return re.sub(r'\*.*\*', '', response)


class KeywordChecker(Instruction):
    """Check the exisitence of certain keywords."""

    def build_description(self, *, keywords=None):
        """Build the instruction description.

        Args:
          keywords: A sequence of strings representing the keywords that are
            expected in the response.

        Returns:
          A string representing the instruction description.
        """

        if not keywords:
            self._keywords = instructions_util.generate_keywords(
                num_keywords=_NUM_KEYWORDS)
        else:
            self._keywords = keywords
        self._keywords = sorted(self._keywords)

        self._description_pattern = (
            'Include keywords {keywords} in the response.')

        return self._description_pattern.format(keywords=self._keywords)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'keywords': self._keywords}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['keywords']

    def check_following(self, value):
        """Check if the response contain the expected keywords."""
        for keyword in self._keywords:
            if not re.search(keyword, value, flags=re.IGNORECASE):
                return False
        return True


class KeywordFrequencyChecker(Instruction):
    """Check the keyword frequency."""

    def build_description(self,
                          *,
                          keyword=None,
                          frequency=None,
                          relation=None):
        """Build the instruction description.

        Args:
          keyword: A string representing a keyword that is expected in the response.
          frequency: An integer specifying the number of times `keyword` is expected
            to appear in the response.
          relation: A string in (`less than`, `at least`), defining the relational
            operator for comparison.
            Two relational comparisons are supported for now:
            if 'less than', the actual number of occurrences < frequency;
            if 'at least', the actual number of occurrences >= frequency.

        Returns:
          A string representing the instruction description.
        """
        if not keyword:
            self._keyword = instructions_util.generate_keywords(
                num_keywords=1)[0]
        else:
            self._keyword = keyword.strip()

        self._frequency = frequency
        if self._frequency is None or self._frequency < 0:
            self._frequency = random.randint(1, _KEYWORD_FREQUENCY)

        if relation is None:
            self._comparison_relation = random.choice(_COMPARISON_RELATION)
        elif relation not in _COMPARISON_RELATION:
            raise ValueError(
                'The supported relation for comparison must be in '
                f'{_COMPARISON_RELATION}, but {relation} is given.')
        else:
            self._comparison_relation = relation

        self._description_pattern = (
            'In your response, the word {keyword} should appear {relation} ' +
            '{frequency} times.')

        return self._description_pattern.format(
            keyword=self._keyword,
            relation=self._comparison_relation,
            frequency=self._frequency)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'keyword': self._keyword,
            'frequency': self._frequency,
            'relation': self._comparison_relation
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['keyword', 'frequency', 'relation']

    def check_following(self, value):
        """Checks if the response contain the keyword with required
        frequency."""
        actual_occurrences = len(
            re.findall(self._keyword, value, flags=re.IGNORECASE))

        if self._comparison_relation == _COMPARISON_RELATION[0]:
            return actual_occurrences < self._frequency
        elif self._comparison_relation == _COMPARISON_RELATION[1]:
            return actual_occurrences >= self._frequency


class NumberOfWords(Instruction):
    """Checks the number of words."""

    def build_description(self, *, num_words=None, relation=None):
        """Build the instruction description.

        Args:
          num_words: An integer specifying the number of words contained in the
            response.
          relation: A string in (`less than`, `at least`), defining the relational
            operator for comparison.
            Two relational comparisons are supported for now:
            if 'less than', the actual number of words < num_words;
            if 'at least', the actual number of words >= num_words.

        Returns:
          A string representing the instruction description.
        """

        self._num_words = num_words
        if self._num_words is None or self._num_words < 0:
            self._num_words = random.randint(_NUM_WORDS_LOWER_LIMIT,
                                             _NUM_WORDS_UPPER_LIMIT)

        if relation is None:
            self._comparison_relation = random.choice(_COMPARISON_RELATION)
        elif relation not in _COMPARISON_RELATION:
            raise ValueError(
                'The supported relation for comparison must be in '
                f'{_COMPARISON_RELATION}, but {relation} is given.')
        else:
            self._comparison_relation = relation

        self._description_pattern = (
            'Answer with {relation} {num_words} words.')

        return self._description_pattern.format(
            relation=self._comparison_relation, num_words=self._num_words)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'num_words': self._num_words,
            'relation': self._comparison_relation
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_words', 'relation']

    def check_following(self, value):
        """Checks if the response contains the expected number of words."""
        num_words = instructions_util.count_words(value)

        if self._comparison_relation == _COMPARISON_RELATION[0]:
            return num_words < self._num_words
        elif self._comparison_relation == _COMPARISON_RELATION[1]:
            return num_words >= self._num_words


class JsonFormat(Instruction):
    """Check the Json format."""

    def build_description(self):
        self._description_pattern = (
            'Entire output should be wrapped in JSON format. You can use markdown'
            ' ticks such as ```.')
        return self._description_pattern

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        value = (value.strip().removeprefix('```json').removeprefix(
            '```Json').removeprefix('```JSON').removeprefix(
                '```').removesuffix('```').strip())
        try:
            json.loads(value)
        except ValueError as _:
            return False
        return True


class ParagraphFirstWordCheck(Instruction):
    """Check the paragraph and the first word of the nth paragraph."""

    def build_description(self,
                          num_paragraphs=None,
                          nth_paragraph=None,
                          first_word=None):
        r"""Build the instruction description.

        Args:
          num_paragraphs: An integer indicating the number of paragraphs expected
            in the response. A paragraph is a subset of the string that is
            expected to be separated by '\n\n'.
          nth_paragraph: An integer indicating the paragraph number that we look at.
            Note that n starts from 1.
          first_word: A string that represent the first word of the bth paragraph.

        Returns:
          A string representing the instruction description.
        """
        self._num_paragraphs = num_paragraphs
        if self._num_paragraphs is None or self._num_paragraphs < 0:
            self._num_paragraphs = random.randint(1, _NUM_PARAGRAPHS)

        self._nth_paragraph = nth_paragraph
        if (self._nth_paragraph is None or self._nth_paragraph <= 0
                or self._nth_paragraph > self._num_paragraphs):
            self._nth_paragraph = random.randint(1, self._num_paragraphs + 1)

        self._first_word = first_word
        if self._first_word is None:
            self._first_word = instructions_util.generate_keywords(
                num_keywords=1)[0]
        self._first_word = self._first_word.lower()

        self._description_pattern = (
            'There should be {num_paragraphs} paragraphs. ' +
            'Paragraphs and only paragraphs are separated with each other by two '
            + "new lines as if it was '\\n\\n' in python. " +
            'Paragraph {nth_paragraph} must start with word {first_word}.')

        return self._description_pattern.format(
            num_paragraphs=self._num_paragraphs,
            nth_paragraph=self._nth_paragraph,
            first_word=self._first_word)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'num_paragraphs': self._num_paragraphs,
            'nth_paragraph': self._nth_paragraph,
            'first_word': self._first_word
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_paragraphs', 'nth_paragraph', 'first_word']

    def check_following(self, value):
        """Checks for required number of paragraphs and correct first word.

        Args:
          value: a string representing the response. The response may contain
            paragraphs that are separated by two new lines and the first word of
            the nth paragraph will have to match a specified word.

        Returns:
          True if the number of paragraphs is the same as required and the first
          word of the specified paragraph is the same as required. Otherwise, false.
        """

        paragraphs = re.split(r'\n\n', value)
        num_paragraphs = len(paragraphs)

        for paragraph in paragraphs:
            if not paragraph.strip():
                num_paragraphs -= 1

        # check that index doesn't go out of bounds
        if self._nth_paragraph <= num_paragraphs:
            paragraph = paragraphs[self._nth_paragraph - 1].strip()
            if not paragraph:
                return False
        else:
            return False

        first_word = ''
        punctuation = {'.', ',', '?', '!', "'", '"'}

        # get first word and remove punctuation
        word = paragraph.split()[0].strip()
        # TODO(jeffrey): make more complex?
        word = word.lstrip("'")
        word = word.lstrip('"')

        for letter in word:
            if letter in punctuation:
                break
            first_word += letter.lower()

        return (num_paragraphs == self._num_paragraphs
                and first_word == self._first_word)


# TODO(jeffrey) add relation - at least/at most?
class KeySentenceChecker(Instruction):
    """Check the existence of certain key sentences."""

    def build_description(self, key_sentences=None, num_sentences=None):
        """Build the instruction description.

        Args:
          key_sentences: A sequences of strings representing the key sentences that
            are expected in the response.
          num_sentences: The number of key sentences that are expected to be seen in
            the response.

        Returns:
          A string representing the instruction description.
        """

        if not key_sentences:
            # TODO(jeffrey) make a generate sentences function? wonderwords package
            self._key_sentences = set(['For now, this is fine.'])
        else:
            self._key_sentences = key_sentences

        if not num_sentences:
            self._num_sentences = random.randint(1, len(self._key_sentences))
        else:
            self._num_sentences = num_sentences

        self._description_pattern = (
            'Include {num_sentences} of the following sentences {key_sentences}'
        )

        return self._description_pattern.format(
            num_sentences=self._num_sentences,
            key_sentences=self._key_sentences)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'num_sentences': self._num_sentences,
            'key_sentences': list(self._key_sentences)
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['num_sentences', 'key_sentences']

    def check_following(self, value):
        """Checks if the response contains the expected key sentences."""
        count = 0
        sentences = instructions_util.split_into_sentences(value)
        for sentence in self._key_sentences:
            if sentence in sentences:
                count += 1

        return count == self._num_sentences


class ForbiddenWords(Instruction):
    """Checks that specified words are not used in response."""

    def build_description(self, forbidden_words=None):
        """Build the instruction description.

        Args:
          forbidden_words: A sequences of strings representing words that are not
            allowed in the response.

        Returns:
          A string representing the instruction description.
        """

        if not forbidden_words:
            self._forbidden_words = instructions_util.generate_keywords(
                num_keywords=_NUM_KEYWORDS)
        else:
            self._forbidden_words = list(set(forbidden_words))
        self._forbidden_words = sorted(self._forbidden_words)
        self._description_pattern = (
            'Do not include keywords {forbidden_words} in the response.')

        return self._description_pattern.format(
            forbidden_words=self._forbidden_words)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {'forbidden_words': self._forbidden_words}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['forbidden_words']

    def check_following(self, value):
        """Check if the response does not contain the expected keywords."""
        for word in self._forbidden_words:
            if re.search(r'\b' + word + r'\b', value, flags=re.IGNORECASE):
                return False
        return True


class RephraseParagraph(Instruction):
    """Checks that the paragraph is rephrased."""

    def build_description(self, *, original_paragraph, low, high):
        """Builds the instruction description.

        Args:
          original_paragraph: A string presenting the original paragraph. The
            rephrases response should have betweeb low-high words in common.
          low: An integer presenting the lower bound of similar words.
          high: An integer representing the upper bound of similar words.

        Returns:
          A string representing the instruction description.
        """
        # TODO(jeffrey) make more encompassing
        self._original_paragraph = original_paragraph
        self._low = low
        self._high = high

        self._description = (
            'Rephrase the following paragraph: ' +
            '{original_paragraph}\nYour response should have ' +
            'between {low} and {high} of the same words. ' +
            'Words are the same if and only if all of the ' +
            'letters, ignoring cases, are the same. For ' +
            "example, 'run' is the same as 'Run' but different " + "to 'ran'.")

        return self._description.format(original_paragraph=original_paragraph,
                                        low=self._low,
                                        high=self._high)

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return {
            'original_paragraph': self._original_paragraph,
            'low': self._low,
            'high': self._high
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['original_paragraph', 'low', 'high']

    def check_following(self, value):
        val_words = re.findall(r'\w+', value.lower())
        original_words = re.findall(r'\w+', self._original_paragraph.lower())
        similar_words = 0

        dict_val = collections.Counter(val_words)
        dict_original = collections.Counter(original_words)

        for word in dict_original:
            similar_words += min(dict_original[word], dict_val[word])

        return similar_words >= self._low and similar_words <= self._high


class TwoResponsesChecker(Instruction):
    """Check that two responses were given."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'Give two different responses. Responses and only responses should'
            ' be separated by 6 asterisk symbols: ******.')
        return self._description_pattern

    def get_instruction_args(self):
        """Returns the keyword args of `build_description`."""
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks if the response has two different answers.

        Args:
          value: A string representing the response.

        Returns:
          True if two responses are detected and false otherwise.
        """
        valid_responses = list()
        responses = value.split('******')
        for index, response in enumerate(responses):
            if not response.strip():
                if index != 0 and index != len(responses) - 1:
                    return False
            else:
                valid_responses.append(response)
        return (len(valid_responses) == 2
                and valid_responses[0].strip() != valid_responses[1].strip())


class RepeatPromptThenAnswer(Instruction):
    """Checks that Prompt is first repeated then answered."""

    def build_description(self, *, prompt_to_repeat=None):
        """Build the instruction description.

        Args:
          prompt_to_repeat: The prompt that is meant to be repeated.

        Returns:
          A string representing the instruction description.
        """
        if not prompt_to_repeat:
            raise ValueError('prompt_to_repeat must be set.')
        else:
            self._prompt_to_repeat = prompt_to_repeat
        self._description_pattern = (
            'First repeat the request word for word without change,'
            ' then give your answer (1. do not say any words or characters'
            ' before repeating the request; 2. the request you need to repeat'
            ' does not include this sentence)')
        return self._description_pattern

    def get_instruction_args(self):
        return {'prompt_to_repeat': self._prompt_to_repeat}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['prompt_to_repeat']

    def check_following(self, value):
        if value.strip().lower().startswith(
                self._prompt_to_repeat.strip().lower()):
            return True
        return False


class EndChecker(Instruction):
    """Checks that the prompt ends with a given phrase."""

    def build_description(self, *, end_phrase=None):
        """Build the instruction description.

        Args:
          end_phrase: A string representing the phrase the response should end with.

        Returns:
          A string representing the instruction description.
        """
        self._end_phrase = (end_phrase.strip()
                            if isinstance(end_phrase, str) else end_phrase)
        if self._end_phrase is None:
            self._end_phrase = random.choice(_ENDING_OPTIONS)
        self._description_pattern = (
            'Finish your response with this exact phrase {ender}. '
            'No other words should follow this phrase.')
        return self._description_pattern.format(ender=self._end_phrase)

    def get_instruction_args(self):
        return {'end_phrase': self._end_phrase}

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['end_phrase']

    def check_following(self, value):
        """Checks if the response ends with the expected phrase."""
        value = value.strip().strip("\"").lower()
        self._end_phrase = self._end_phrase.strip().lower()
        return value.endswith(self._end_phrase)


class TitleChecker(Instruction):
    """Checks the response for a title."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'Your answer must contain a title, wrapped in double angular brackets,'
            ' such as <<poem of joy>>.')
        return self._description_pattern

    def get_instruction_args(self):
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks if the response contains a title."""
        pattern = r'<<[^\n]+>>'
        re_pattern = re.compile(pattern)
        titles = re.findall(re_pattern, value)

        for title in titles:
            if title.lstrip('<').rstrip('>').strip():
                return True
        return False


class LetterFrequencyChecker(Instruction):
    """Checks letter frequency."""

    def build_description(self,
                          *,
                          letter=None,
                          let_frequency=None,
                          let_relation=None):
        """Build the instruction description.

        Args:
          letter: A string representing a letter that is expected in the response.
          let_frequency: An integer specifying the number of times `keyword` is
            expected to appear in the response.
          let_relation: A string in (`less than`, `at least`), defining the
            relational operator for comparison. Two relational comparisons are
            supported for now; if 'less than', the actual number of
            occurrences < frequency; if 'at least', the actual number of
            occurrences >= frequency.

        Returns:
          A string representing the instruction description.
        """
        if (not letter or len(letter) > 1 or ord(letter.lower()) < 97
                or ord(letter.lower()) > 122):
            self._letter = random.choice(list(string.ascii_letters))
        else:
            self._letter = letter.strip()
        self._letter = self._letter.lower()

        self._frequency = let_frequency
        if self._frequency is None or self._frequency < 0:
            self._frequency = random.randint(1, _LETTER_FREQUENCY)

        if let_relation is None:
            self._comparison_relation = random.choice(_COMPARISON_RELATION)
        elif let_relation not in _COMPARISON_RELATION:
            raise ValueError(
                'The supported relation for comparison must be in '
                f'{_COMPARISON_RELATION}, but {let_relation} is given.')
        else:
            self._comparison_relation = let_relation

        self._description_pattern = (
            'In your response, the letter {letter} should appear {let_relation}'
            ' {let_frequency} times.')

        return self._description_pattern.format(
            letter=self._letter,
            let_frequency=self._frequency,
            let_relation=self._comparison_relation,
        )

    def get_instruction_args(self):
        """Returns the keyword args of build description."""
        return {
            'letter': self._letter,
            'let_frequency': self._frequency,
            'let_relation': self._comparison_relation
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['letter', 'let_frequency', 'let_relation']

    def check_following(self, value):
        """Checks that the response contains the letter at the right
        frequency."""
        value = value.lower()
        letters = collections.Counter(value)

        if self._comparison_relation == _COMPARISON_RELATION[0]:
            return letters[self._letter] < self._frequency
        else:
            return letters[self._letter] >= self._frequency


class CapitalLettersEnglishChecker(Instruction):
    """Checks that the response is in english and is in all capital letters."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'Your entire response should be in English, and in all capital letters.'
        )
        return self._description_pattern

    def get_instruction_args(self):
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks that the response is in English and in all capital
        letters."""
        assert isinstance(value, str)

        try:
            return value.isupper() and langdetect.detect(value) == 'en'
        except langdetect.LangDetectException as e:
            # Count as instruction is followed.
            logging.error('Unable to detect language for text %s due to %s',
                          value, e)  # refex: disable=pytotw.037
            return True


class LowercaseLettersEnglishChecker(Instruction):
    """Checks that the response is in english and is in all lowercase
    letters."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'Your entire response should be in English, and in all lowercase'
            ' letters. No capital letters are allowed.')
        return self._description_pattern

    def get_instruction_args(self):
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks that the response is in English and in all lowercase
        letters."""
        assert isinstance(value, str)

        try:
            return value.islower() and langdetect.detect(value) == 'en'
        except langdetect.LangDetectException as e:
            # Count as instruction is followed.
            logging.error('Unable to detect language for text %s due to %s',
                          value, e)  # refex: disable=pytotw.037
            return True


class CommaChecker(Instruction):
    """Checks the response for no commas."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'In your entire response, refrain from the use of any commas.')
        return self._description_pattern

    def get_instruction_args(self):
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks that the response does not contain commas."""
        return not re.search(r'\,', value)


class CapitalWordFrequencyChecker(Instruction):
    """Checks frequency of words with all capital letters."""

    def build_description(
        self,
        capital_frequency=None,
        capital_relation=None,
    ):
        """Build the instruction description.

        Args:
          capital_frequency: An integer that represents the number of words that
            should be in all capital letters.
          capital_relation: A string that is 'at least' or 'at most' that refers to
            the frequency.

        Returns:
          A string representing the instruction description.
        """
        self._frequency = capital_frequency
        if self._frequency is None:
            self._frequency = random.randint(1, _ALL_CAPITAL_WORD_FREQUENCY)

        self._comparison_relation = capital_relation
        if capital_relation is None:
            self._comparison_relation = random.choice(_COMPARISON_RELATION)
        elif capital_relation not in _COMPARISON_RELATION:
            raise ValueError(
                'The supported relation for comparison must be in '
                f'{_COMPARISON_RELATION}, but {capital_relation} is given.')

        self._description_pattern = (
            'In your response, words with all capital letters should appear'
            ' {relation} {frequency} times.')

        return self._description_pattern.format(
            frequency=self._frequency, relation=self._comparison_relation)

    def get_instruction_args(self):
        """Returns the keyword args of build description."""
        return {
            'capital_frequency': self._frequency,
            'capital_relation': self._comparison_relation,
        }

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return ['capital_frequency', 'capital_relation']

    def check_following(self, value):
        """Checks the frequency of words with all capital letters."""
        # Hyphenated words will count as one word
        words = instructions_util.nltk.word_tokenize(value)
        capital_words = [word for word in words if word.isupper()]

        capital_words = len(capital_words)

        if self._comparison_relation == _COMPARISON_RELATION[0]:
            return capital_words < self._frequency
        else:
            return capital_words >= self._frequency


class QuotationChecker(Instruction):
    """Checks response is wrapped with double quotation marks."""

    def build_description(self):
        """Build the instruction description."""
        self._description_pattern = (
            'Wrap your entire response with double quotation marks.')
        return self._description_pattern

    def get_instruction_args(self):
        """Returns the keyword args of build description."""
        return None

    def get_instruction_args_keys(self):
        """Returns the args keys of `build_description`."""
        return []

    def check_following(self, value):
        """Checks if the response is wrapped with double quotation marks."""
        value = value.strip()
        return len(value) > 1 and value[0] == '"' and value[-1] == '"'
